Clutch servo

[B87UL]

Brian

Having recently re-pistoned my 3.4s in the chassis and then gone through the exercise of re-setting the tappets, finishing only this week, you have my greatest sympathy if you are removing the engine. What a chore !!

I am lucky as I have all the tooling necessary including four post lift, travelling lift beam jack and overhead crane. Once again next Winter I shall need to drop the suspension and engine to cure an oil leak between bell housing and gearbox. Not looking forward to it.

Most certainly if you have no graphite showing above the carrier face you will soon need to replace the unit and no doubt like me you cannot rest until you have sorted it out. Good luck with your engine removal.

It sounds as though you are extracting the engine from the top? Frankly I prefer a manual operated chain block rather than electric as I find the latter tends to have abrupt movements with poor control while the manual 2 ton blocks are nicely low geared and very controlled. If you want to temporarily loan a new 2 ton manual block give me a ring on 01733 233294, I am quite close to your location.

We have a misunderstanding regarding the slave cylinder back stop arrangement. I will attempt to insert an image of a backstop adjuster with this text, if that is not successful then ring me and I will describe the design.

This arrangement is designed to positively allow the release bearing to withdraw clear of the clutch pressure plate, but it also limits the amount of travel that the slave cylinder can withdraw under influence of the return spring. This withdrawal movement is adjustable and allows some freedom to alter the clutch bite position. If the image post is successful you will see a long set screw positioned on a bracket limiting the withdrawal movement of the clutch arm.

From memory it is necessary to shorten the push rod by about 6 mm, but when completed it all provides a clear withdraw and the required stroke to declutch, without over-stroking the clutch. It is a very simple and easy modification.

[Martec]

Hi,
To finish my story off regarding the clutch release bearing and experiments with a 3/4" slave against the original 7/8" slave.

I took my engine and gearbox out through the bottom, by jacking up the car, rolling out the front axle, lowering the engine and box onto a very low trolley, pulling it out and refitting the front axle. The clutch plate was still in excellent condition and due to the unknown quality of new clutch plates it was refitted. The release bearing was replaced and all returned plus Norman's back stop modification in time for a run to the CMC MkII open day.

This back stop arrangement of Norman's is very good, I finally set the external gap at 4mm which gives a 2.4mm gap between the release bearing and clutch plate and lifts the bite point off the floor. I did over 500 miles like this but decided to try a smaller slave cylinder, it was fitted up and bled this morning and I immediately noticed a much heavier pedal action, but the bite point was much higher with an external gap of 5mm at the back stop. After 20 minutes driving around a local estate and an aching hip I took the 3/4" slave out and refitted the correct 7/8" slave cylinder. Another drive confirmed it was almost as good as our more modern cars on diaphragm clutches.

My conclusion is that the original 7/8" slave cylinder, plus an aftermarket mini servo and Norman's back stop give a nice light clutch action but with a lower bite point, which I can live with.